Breech-closing mechanism for automatic firearms.



c. L. ROSS. BBEEGH GLOSING MECHANISM FOR AUTOMATIG FIREARMS.

APPLIOATIOR 311,31) APR. 30,1906.

Patented Apr. 12, 1910.

2 SHEETS-SHEET 1.

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C. L. ROSS.

BREEOH CLOSING MECHANISM FOR AUTOMATIC FIREARMS.

APPLIOATION FILED APR. 30, 1906.

954,543, Patented Apr.'12,1910.

2 SHEETSSHEET 2.

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CHARLES L. ROSS, OF BALNAGOWAN CASTLE, COUNTY OF ROSS, SCOTLAND.

BREECH-CLOSING MECHANISM FOR AUTOMATIC FIREARMS.

Patented Apr. 12, 1910..

Serial No. 314,594.

To all whom it may concern:

Be it known that I, CHARLES HENRY AUGUSTUS FREDERICK LOCKHART Ross,baronet, a citizen of Great Britain, and resident of Balnagowan Castle,in the county of Ross, Scotland, have invented certain new and usefulImprovements in Breech-(Hos ing Mechanism for Automatic Firearms, ofwhich the following is a full, clear, and exact specification.

This invention relates to the breech closing mechanism of repeatingfirearms of the class in which the recoil from the discharge of onecart-ridge is utilized to open the breech, move the next succeedingcartridge from the magazine into the firing chamber, close the breech,and otherwise prepare the firearm for the next discharge.

Although the invention is applicable to various forms of firearms, it ishere shown in connection with that type of automatic pistol in which theundischarged cartridges are generally contained in a magazine inclosedwithin the grip or handle of the pistol.

Figure 1 is a plan view of a pistol embodying this invention, and showsthe parts in the locked or firing position. Fig. 2 is a side view ofFig. 1. Fig. 3 is a side view of the pistol with the parts in theirunlocked position. Fig. 4 is a plan of the pistol in section on the line4 of Fig. 2. Fig. 5 is a rear view of Fig. 3.

The barrel 16 and the bolt 26 are adapted to slide endwise in ways 13(Fig. 5) formed in the frame 11. The cartridges are carried in aconveniently adjacent magazine (not shown) preferably. contained withinthe grip or handle 12 appurtenant to the frame and are lifted from themagazine by the re-' coil of the discharge into line with the chamber 17(Fig. 4) formed in the breech end of the barrel. The firing pin, searextractor and ejector are carried in the bolt 26. As these parts andalso the mechanism by which the cartridges are lifted from the magazineand carried into line with the chamber form no part of the presentinvention, they are neither shown nor described herein.

The barrel 16 has connected to it a pair of barrel links 18 and 19.These links are pivoted at their front ends by trunnions 14 and 15 tothe barrel 16 and are connected at their rear ends by means of the pivotpin 20 to the rear ends of a pair of bolt links 27 and 28. These latterare pivoted at their front ends at 29 and 30 to the bolt 26. When theparts are in the firing position shown in Figs. 1, 2 and 3, these linkslie folded side by side, forming a locking toggle device each barrellink 18 or 19 lying next to its corresponding bolt link 27 or 28, thetwo links 27 and 28 being separated by the bolt 26. The pivot pin 20extends outwardly from the links on both sides and is provided with ahead 21 on one end, and a nut 22 on the other end, which is preferablyof the same size as the head 21. A collar 23 is carried on the pivot 20between the bolt links 27 and 28. The links 18 and 19 have formed ontheir outer and under surfaces a pair of cams 36 and 37, which areadapted to cooperate with a pair of cam surfaces 38 and 39 formed on thelugs 40 and 41 appurtenant to the frame 11. The rear side of the lugs 40and 41 is shaped at 42 and 43 to fit the head 21 and the nut 22 of therear pivot 20.

The above described parts are all so disposed that when they are in thefiring position as shown in Figs. 1, 2 and 4, with the bolt 26 incontact with the breech end 24 of the barrel, the cams 36 and 37 of thebarrel links 18 and 19 are in contact respectively with the cam surface38 and 39, the pivot head 21 and the pivot nut 22 resting at the sametime against the surfaces 42 and 43. This disposition of the parts inthe firing position 'is preferably so arranged that the axis of the rearpivot 20 may drop a little below the plane of the axes of the frontpivots 14 and 15 and 29 and 30, as shown in Fig. 2, the line 4 passingthrough the center of the pivot 20 while the line 00 coincides with theplane of the two front pivot axes. This carries the toggle-like deviceto a safe locking position, so that the direct effect of the recoil asbetween the barrel and the bolt tends to hold the toggle in its foldedor locked position.

Upon the meeting faces of the links 18 and 27 and the links 19 and 28are formed interlocking projections 46 and 47 which are curved on theirfront and rear surfaces on arcs struck from the axis of the pivot 21, soas to enable the projections to properly pass by each other andinterlock when the links shut down and fold together in the firingposition. stance 45, is provided against which the barrel may abut justas the parts reach the A suitable stop, as for in-' firing position. Arod 49 secured to the rear end of the bolt and extending through thebracket 50 carries a spring 48 which engages the rear end of the boltand presses it toward the barrel, the bracket 50 sustaining the rearwardthrust of this spring.

The operation of the parts is as follows When a discharge takes place,the pressure of the recoil is exerted against the front end of the bolt26, tending to drive it rearward away from the barrel 16. The bolt,however, being secured to the barrel 16 by means of the connectionsthrough the four links and the interlocking projections 46 and 47'cannot move backward except by carrying the barrel with it. This actioncauses the cams 36 and 37 to ride up over the cam surfaces 38 and 39,thus raising the rear ends of the links and unlocking the toggle,thereby allowing the bolt to slide backwards to the position shown inFig. 3, the movement of the barrel being arrested by the shoulders 33and 34 coming in contact with the frame lugs 40 and 41, (Fig. Theinterlocking projections 46 and 47 offer no resistance to. this upwardmovement of the rear ends of the links on account of the concentricrelation of those projections to the pivotal connection 20 between thelinks. As the bolt 26 moves backwards it compresses the spring 48 untilits movement is arrested by the meeting of the links 27 and 28 with thesurfaces 31 and 32 formed on the bolt. By the time the movement of thebolt is thus arrested, the empty shell is expelled and a new cartridgebrought up into line with the barrel chamber. The pressure of thespring- 48 now carries the bolt forward again, so. that the pivots 29and 30 approach the pivots 14 and 15 and the ends of the links carryingthe pivot 20 drop down to the locking position shown in Figs. 1 and 2.

The interlocking lugs or projections 46 and 47 while not indispensableperform a very important function in securely sustaining the parts intheir firing position, so that the strain of the recoil is more directlytransmitted to and sustained by the trunnions and the barrel withoutexerting any appreciable pressure against the rear pivot 20, therebydiminishing the distance and the number of parts through which thestrains are transmitted, and increasing correspondingly the rigidity ofthe structure. In the case of the firearms of small caliber theseinterlocking lugs may conceivably be dispensed with, but their use isconsidered highly preferable.

The toggle is herein shown as having a pair of links on each side of thelongitudinal center of the bolt. For some purposes, however, one pair oflinks may be found sufiicient. But it is considered preferable thus toemploy two pairs of links, disposed sym-- metrically on opposite sidesof the longitudinal center of the firearm. It is not essential, althoughpreferable, that the barrel member to which the links 18 and 19 areconnected shall be integral with the barrel, since that member may be ayoke separately attached to the barrel, this being a considererationeither incident to the method of manufacture, or to the requirements ofother functions of the parts. The firearm is also provided with suitableother mechanism, such as a firing pin sear, trigger, cartridge elevator,etc. to perform the usual functions of an automatic firearm, but thatother mechanism forms no part of the invention described herein, andtherefore it is not herein shown and described.

I claim as my invention 1. In a recoil operated firearm, a barrel and abreech bolt mounted for sliding movement, and a toggle formed of linkspivotally connected to the barrel and bolt members, respectively, andconnected with each other to fold together backwardly from said pivotalconnections when in firing position.

2. In a recoil operated firearm, means for locking the bolt, comprisinga toggle formed of links pivotally connected to the bolt and barrelmembers respectively, and connected with each other to fold togetherwhen in firing position, the links being provided with lugs situatedbetween the pivotal connections which interlock when in said position,and unlock when unfolded from the said firing position.

3. In a recoil operated firearm, a barrel and a breech bolt mounted forsliding movement, a toggle formed of links pivotally connected to thebarrel and bolt members, respectively, and connected with each other tofold backwardly together when in firing position, and means forunfolding the links as they are carried back by the sliding movement ofthe barrel and bolt due to the recoil.

4. In a recoil operated firearm, a barrel and a breech bolt therefor,both mounted for sliding movement, a toggle formed of links pivotallyconnected to the barrel and bolt members, respectively, and pivotallyconnected with each other to fold backwardly together when in firingposition, and a camlike abutment interposed in the pathway of the linksto unfold the toggle as the parts are forced backwardly by the recoil.

5. In a recoil operated firearm, means for locking the bolt, comprisinga toggle formed of links pivotally connected to the bolt and barrelmembers respectively, and connected with each other to fold themtogether when in firing position, the links being provided withinterlocking lugs situated between their pivotal connections 1nconcentric relation to the axis of the connection between the two links.

6. In a recoil operated firearm, a barrel and a breech bolt thereformounted for sliding movement, and a toggle composed of two pairs oflinks pivotally connected to the barrel and bolt members, respectively,and pivotally connected together to fold backwardly togetherside by sideto their locked and firing position.

7. In a recoil operated firearm, a barrel and a breech bolt thereformounted for sliding movement, a toggle composed of two pairs of linkspivotally connected to the barrel and bolt members, respectively, andpivotally connected together to fold backwardly together side by side totheir locked position, and means for supporting the links in the latterposition with their pivotal connections disposed near a plane which issubstantially at right angles with the path of the first openingmovement of the links.

8. In a recoil operated firearm, means for locking the bolt to thebarrel comprising a toggle composed of a pair of links pivotallyconnected to the barrel, a pair of shorter links pivotally connected tothe bolt, a pivotal connection between the two pairs of links, wherebythey lie folded together when in firing position, and means forsupporting the toggle in a position in which the pivotal connectionbetween the two pairs of links is carried slightly past the plane of theother pivotal connections.

9. In a recoil operated firearm, a frame, a barrel, and a bolt mountedfor sliding movement in the frame, a link connected to the barrel, ashorter link connected to the bolt, and a pivotal connection between theother ends of the two links whereby the links when in their firingposition are folded backwardly together side by side in the direction ofrecoil.

10. In a recoil operated firearm, a frame, a barrel and a bolt mountedfor sliding action on the frame, a link connected at one end to thebarrel, a shorter link connected at one end to the bolt, a connectionpivotally joining the other ends of the two links, whereby the linkswhen in firing position lie folded together side by side extending inthe direct-ion of the recoil, and means for engaging and unfolding thelinks as they are carried back by the recoil.

11. In a recoil operated firearm, the combination with a sliding barrel,and a sliding bolt, of a barrel link connected at its front end to thebarrel, a shorter bolt link connected at its front end to the bolt, andadapted to swing in a plane overlapping the plane of movement of thebarrel link, where-V by they lie folded backwardly together in theirlocked position, a connection joining the rear ends of the two links,and means for engaging the said rear ends and unfolding the links asthey are moved back by the recoil.

12. In a recoil operated firearm, the combination with a barrel, and asliding bolt, of a link connected at its front end to the barrel, ashorter link connected at its front end to the bolt, a connectionjoining the rear ends of the two links, and means for interlocking thelinks when folded backwardly together in the firing position.

13. In a recoil operated firearm, a frame, a sliding barrel, a slidingbolt, a link connected at its front end to the barrel, a shorter linkconnected at its front end to the bolt, a connection joining the rearends of the two links, interlocking means on the meeting faces of thetwo links, and means for engaging and-raising the connected rear ends ofthe links to unlock them as they are moved back by the recoil of thefirearm.

14. In a recoil operated firearm, the combination with a frame, a barreland a sliding bolt, of a link connected at its front end to the barrel,a shorter link connected at its front end to the bolt, a pivotalconnection joining the rear ends of the two links, whereby they areadapted to swing backwardly in overlapping planes and lie foldedtogether, interlocking means on the meeting faces of the two links, andmeans for raising the connected rearward ends of the links to unfoldthem forwardly as they are-moved back by the recoil.

15. In a recoil operated firearm, the combination with a frame, asliding barrel, and a sliding bolt, of a link connected at its front endto the barrel, a link connected at its front end to the bolt, a pivotalconnection joining the rear ends of the two links, where by they liefolded backwardly together in the firing position, and cooperating camsurfaces appurtenant respectively to one of the links and the framewhereby the recoil unfolds the links to unlock the bolt.

16. In a recoil operated firearm, the combination with a frame a slidingbarrel and asliding bolt, of a link pivotally connected at its front endto the barrel, a shorter link pivotally connected at its front end tothe bolt, and a pivotal connection joining the rear ends of the twolinks whereby they fold backwardly together in the firing position, thethree pivotal axes of the links being so disposed that the axis of thepivotal connection of the links lies below the common plane of the othertwo axes when the parts are in the firing position. i

17 In a recoil operated firearm, a sliding barrel, a sliding bolt, andmeans for locking the bolt to the barrel, comprising a toggle composedof a pair of links pivotally connected to the barrel, a pair of shorterlinks pivotally connected to the bolt, a pivotal connection between thetwo pairs of links, whereby they lie folded backwardly together when inlocked position, means for supporting the toggle in a position in whichthe pivotal connection between the two pairs name to this specificationin the presence of of links is carried slightly past the plane of twosubscribing Witnesses. the other pivotal connections and inclinedabutlnents interposed in the pathway of the CHARLES ROSS 5 toggle tounlock it as it is carried back by Witnesses:

the recoil. ERNEST F. WtiRTELE,

I11 testimony whereof I have signed my THOMAS CRAIG.

